A third dose of vaccine, but not the last?

Céline Géraud, edited by Sonia Chemaa 06:21, December 09, 2021

INTERVIEW

In the midst of the recall campaign, the need for a fourth dose against Covid-19 raises questions.

On Wednesday, Jean-François Delfraissy, president of the Scientific Council, estimated in the Senate that a fourth dose would be "possible".

An opinion shared by Benjamin Davido, infectious disease specialist.

"We saw that the second dose ran out of steam after five months."

A one-year immunity? 

Hence the hypothesis of a fourth dose, only one month after the launch of the vaccination campaign with the third.

"We want to think that the third dose, as it simulates the antibody level stronger and higher, it will take longer for this immunity to decrease."

An immunity which is estimated at one year.

But at a time when the Omicron variant is spreading, for the infectious disease specialist, "the real question is whether this kinetics of decrease in antibodies will be the same with Omicron if it becomes the majority?"

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A third dose but may not be the last

The epidemiologist Didier Pittet, guest of Romain Desarbres in Europe Midi on Wednesday, specified that a fourth dose "will depend on the evolution of the pandemic" and that "nobody can say it even today". What is certain, for Benjamin Davido, is that there will be booster doses. "We have to stop counting. And then, maybe at some point, we will come up with another technique of recombinant proteins, for example on a more stable vaccine which will make it possible to have a lasting immunity. Now, we don't have these data in order to be able to estimate that this third will be the last. So it seems quite legitimate to be included in a later dose. " A fourth dose would therefore, for the moment, not be a simple hypothesis.